CUSTOM-MADE MASSIVE UNICONDYLAR FEMORAL REPLACEMENT: A TEN YEAR FOLLOW-UP AND COMPARISON OF FUNCTIONAL OUTCOME WITH DISTAL FEMORAL REPLACEMENT

Abstract

Introduction: We present a review of the long-term results of custom-made massive unicondylar femoral replacement for reconstruction following tumour excision, and compare the functional outcome of this procedure with prosthetic distal femoral replacement.

Method: Using our centre’s endoprosthetic database we identified and analysed all cases of massive unicondylar femoral replacement performed at our unit (group 1). Patients were evaluated for function, (Musculoskeletal Tumour Society System), and for stability (adapted from Oxford Knee Score). An age and sex-matched cohort of patients who had undergone distal femoral replacements for similar pathologies, and in who the follow-up was of a comparable time period (group 2) was evaluated in an identical manner. Statistical analysis was performed on the results.

Results: Twelve cases of massive unicondylar replacement have been performed between 1990 and 2001, for a variety of malignant and benign tumours. There have been no incidences of infection, aseptic loosening or tumour recurrence. One patient has died of metastatic disease and another has undergone revision to distal femoral replacement for osteoarthritis. Of the remaining ten patients, nine were available for assessment Each of the two groups consisted of 5 males and 4 females, with mean age 48 years in group 1 and 49 years in group 2. The average follow-up since surgery in both groups was 10 years. The mean MSTS and stability scores of group 1 were 83% and 3.9 respectively, and 71% and 3.2 for group 2; the difference in scores between groups was statistically significant, (p< 0.02).

Conclusion: With stringent case selection criteria, the custom-made massive unicondylar femoral replacement generally produces a good outcome, with functional results significantly better than distal femoral replacement. This may be because a substantial proportion of the knee joint with at least one cruciate and one collateral ligament are kept intact, thus facilitating enhanced proprioception.